In this cross-sectional investigation of PCa, drinkers and non-drinkers had different relationships between DII and PSA levels (OR: 1.2, 95% Cl: 1-1.44 vs. OR: 0.98, 95% Cl: 0.9–1.07), and DII and abstaining from alcohol were effective in reducing the incidence of PSA (p-value for significant interaction = 0.037). This evidence concerns the gene KLK3 and posterior cortical atrophy.